Extensible and retractable boom construction for cranes



Nav. 18, .19694 R.E.srAuFr-'ER 3,478,894

EXTENSIBLE AND RETRACTABLE BOOM CONSTRUCTION FOR CRANES Filed Nov. 27, 1967 3 SheetsSheet 1 U7 l!) n *r INVENTOR; POSER-r ESTAUFFER Bf UW 46m1- HTToF/YEY Nov. 18, 1969 R. E. STAUFFER 3,478,894

EXTENSIBLE AND RETRACTABLE BOOM CONSTRUCTION FOR CRANES Filed NOV. 27, 1967 -5 Sheets-Sheet 2 Scl m'ENToR; ROBERT EST/UFPER f, www

Nov. 18, 1969 R, E, STAUFFER 3,478,894

EXTENSIBLE AND RETRCTABLE BOOM CONSTRUCTION FOR CRANS Filed Nov. 27, 1967 5 sheets-sheet s I.\' EIYTOR; ROBERT E ,STAUFFfR bmg qw HTTQEWEY,

United States Patent O U.S. Cl. 212-55 8 Claims i ABSTRACT oF THE DISCLOSURE A crane with a boom that has three boom sections. The second and third boom sections are extensible and retractable relatively to the first 'boom section and relatively to each other. There is a hydraulic cylinder to extend and to retract the third boom section relatively to the second boom section. The hydraulic cylinder travels with thel second and third boom sections. A storage length of hydraulic hose may be drawn out and returned to maintain the hydraulic iluid connections to the cylinder as it travels.

The instant invention relate's to cranes, and more particularly to an improved construction for an extensible and retractable boom for such cranes.

There are many applications for cranes for lifting and moving loads of various sizes and descriptions. The usefulness of the cranes stems from the ability to reach any place in a wide area with the crane boom. The crane boom is customarily mounted on a turntable base which permits the boom to swing to any position in a circle. The support for the boom also includes means for raising and lowering the boom, which permits the boom to reach to any elevation within its operating range. Further, the boom is constructed of several extensible and retractable sections, which gives the boom the ability to reach out in a radial direction to dilferent distances within its circle of operation.

The reach of the crane lboom in the radial direction is increased by increasing the number of telescoping sections of the crane boom. There may be only two boom sections, in which the one boom section is extended and retracted relatively to the other boom section. In such a ice hose out from the stored length thereof, and in this manner communication is maintained for. the hydraulic iluid to the hydraulic cylinder.

It is an object of this invention to provide an improved boom construction in which there are second and third lboom sections that are extended and retracted to increase the range of the radial reach of the boom..

It is another object of this invention to provide an improved boom construction that has second and third boom sections with a hydraulic cylinder for extending and retracting the third boom section relatively to the -boom construction the radial reach of the Iboom is detery mined by the extent to which the one boom section may be extended and retracted relatively to the other boom section which remains fixed. The radial reach of such a crane boom is increased -by adding another boom section which may be extended and retracted. In such a boom construction theradial reach of the boom is' determined by the extension and lretraction of two boom sections, which are extended and retracted relatively to the xed boom section, and .'also, the outer one of the boom sections is extended and retracted relatively to the second boom section. e Hydraulic power cylinders are customarily utilized to extend and to retract they boom sections relatively to each other. In the boom construction in which there is ay third boom section that is extended and retracted relatively to a second boom section, the hydraulic cylinder is disposed within the lsecond and third boom sections. When the second and third boom' sections yare extended or retracted relatively to the first boom section the hydraulic cylinder travels or moves with the Iboom sections. It is necessary to maintain the hydraulic hose connections to the hydraulic cylinder in' any position of the latter. This is accomplished by providing a lengthof the hydraulic hose which is stored along the-rst boom section. As the hydraulic cylinder moves it draws the hydraulic second boom section, and means for maintaining connection to the hydraulic cylinder to supply hydraulic operating iluid to the latter.

It is another object of this invention to provide an improved boom construction with second and third boom sections that are extended and retracted relatively to each other by a hydraulic cylinder in which there is a stored length of hydraulic hose that is drawn out and returned as the hydraulic cylinder travels out and returns with the second and third boom sections.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the drawings:

FIG. 1 is a side elevational view of a crane Iboom which is constructed in accordance with this invention;

FIG. 2 is a sectional view of the crane boom, taken on the line 2-2 in FIG. l;

FIG. 3 is a side elevational view of the movable sheave and trolley for the hydraulic hose;

FIG. 4 is a plan view of the movable sheave and trolley, as seen on the line 4-4 in FIG. 3;

FIG. 5 is a schematic view showing the looping of the hydraulic hoses around the sheaves.

In FIG. l there is illustrated a crane boom 10 that is mounted on a suitable platform 11, which may be the chassis or frame of a truck, as in the case of a mobile crane. There is a turntable base 12 on which the crane boom 10 may be swung laterally, usually to any position within a circle. A pedestal 13 stands on the turntable base 12, and extends upwardly and rearwardly to provide a support for a lateral pivot pin 14, by which the crane boom 10 is pivotally mounted on the pedestal 13 to swing upwardly and downwardly to reach to different elevations within the range of operation of the boom 10. There is a lift cylinder 15 which has its base end pivotally connected to the turntable base 12 by a pivot pin 16, and its piston rod end is connected to the boom 10 byI a pivot pin 17. The boom 10 is swung upwardly and downwardly on its pivot pin 14 by extension and retraction, respectively, of the lift cylinder 1'5.

The boom 10 extends forwardly from the pedestal 1,3 as a cantilever beam construction. At the rear end of the boom 10 there is a counterweight 18 to counterbalance the overhanging weight of the boom'10. A winch 19 is also at the rear of the boom 10. A cable 20* extends from the winch over the top of the boom 10 to a head block 21, in which the cable 20 is reeved around the sheaves 22, 23, and then around the sheave 24 of the hook block 25. The winch 19 is operated to pay out and to take up the cable 20 which lowers and raises the hook block 25 to lower and raise any load that may fbe carried by the hook Z9 of the hook block 25.

The boom 10 has a lower or iirst boom section 26 to which the pivot pin 14 of the pedestal 13 is connected. The counterweight 18 and the winch 19 are secured to the first boom section 26. Also the lift cylinder 15 is secured to the rst boom section 26.` Thus, the rst boom section 26 may be moved lupwardly and downwardly on the pivot pin 14 by means of the cylinder 15, but it can- 3 not be extended and retracted, and in this respect it is fixed.

There is an upper or second boom section 27 which is telescopically received within the first boom section 26, and an extension boom section or third boom section 28, which is telescopically received within the second boom section 27. The second boom section 27 may be extended and retracted relatively to te first boom section 26, and the third boom section 28 is carried with the second boom section 27 as the latter is extended and retracted. The third boom section 28 may be extended and retracted relatively to the second boom section 27.

There is a first cylinder 30 which is placed below the first boom section 26 and between its depending side plates 31, 31. The cylinder 30 is connected to the first boom section 26 by a plurality of fiexible or yieldable mounting elements 32 at about the mid-length of the cylinder 30. The piston rod end of the cylinder 30 is connected to the second boom section 27 by a pin 33 which connects to a depending leg 34 on the underside of the second boom section 27. The cylinder 30' is connected to the first boom section 26 at its mid-length in order to avoid excessive bending of the latter, which would cause binding of the piston and piston rod. The cylinder 30 is double acting to extend and to retract the second boom section 27 relatively to the first boom section 26, and the extent of extension is determined by the stroke of the cylinder 30. Below the cylinder 30 there is a fixed guard 35 with a movable part 36 that travels Iwith the second boom section 27 as it is extended and retracted.

The first boom section 26 is of a hollow walled construction, and the second boom section 27 is also of a hollow walled construction, as seen in FIG. 2. A plurality of wear plates 37 are secured to the walls of the second boom section 27 to bear against the inner surfaces of the Walls of the first boom section 26, and to facilitate the movement of the second boom section 27 relatively to the first boom section 26.

The cylinder 30 is double acting, and accordingly, there are hydraulic hose connections to the cylinder 30 at the opposite ends ofthe latter for the supply and return flow of hydraulic fiuid. The cylinder 30 is fixed on the first boom section 26, and the hydraulic lines or hoses are connected to the cylinder 30 in the customary manner. The hydraulic hoses are not illustrated in order to maintain clarity of the drawings.

A second hydraulic cylinder 40 is connected to the second boom section 27 and to the third boom section 28. The cylinder end of the hydraulic cylinder 40 is connected to the second boom section 27 by an upright pin 41 which is secured to the lateral bars 42, 42. in the second boom section 27, as seen in FIG. 2. The piston rod end of the cylinder 40 is connected to the third boom section 28 on an upstanding post 43 by a lateral pin 44. The cylinder 40 is double acting to extend and to retract the third boom section 28 relatively to the second boom section 27, with the length of extension being determined by the stroke of the cylinder 40.

A plurality of wear plates 47 are secured to the third boom section 28 and are directed outwardly therefrom to bear against the inner surfaces of the walls of the second boom section 27 to facilitate the movement of the third boom section 28 relatively to the second boom section 27. At the bottom of the third boom section 28 there are rollers 48, which are adapted to ride on the inside of the second boom section 27, also to facilitate relative movement of the second and third boom sections 27, 28.

Since both the second boom section 27 and the third boom section 28 are extended or move together relatively to the first boom section 26, the cylinder 40 travels relatively to the first boom section 26 with the second and third boom sections 27, 28. Therefore, it is necessary to ymaintain the connections of the hydraulic lines or hoses to the cylinder 40 in all portions of the latter as it travels with the second and third boom sections 27, 28.

At the rear end of the first boom section 26 there is a fixed sheave 50, which is rotatably mounted 0n an upright pin 51 that is secured in a supporting frame 52 on the side wall 31 of the first boom section 26. Below the supporting frame 52 there is a dual hose clamp 53 for receiving hydraulic hoses 45, 46 and for securing the latter by a nut and bolt 54. The hydraulic hoses 45, 46 are led up through the hose clamp 53 and secured by the latter.

At the side of the first boom section 26, on the side wall 31, there is a rail or track 55, which extends along the first boom section 26 and is secured to the side wall 31 of the latter by a plurality of screws 56. A trolley 57 rides along the rail 55. Such trolley 57 has a back plate 58 of a somewhat triangular configuration. At the two upper corners of the back plate 58 there are flanged wheels 59, 60, which are rotatably mounted and which engage on the upper surface of the rail 55. Another flanged wheel 61 is rotatably mounted on the lower corner of the back plate 58 and engages the bottom surface of the rail 55. Each flanged wheel is secured to the back plate 58 by nut and bolt means `62, with suitable bearing means for free rotation of the flanged wheels 59, 60, 61. The trolley 57 may ride back and forth along the rail 55. A short shaft 63 is secured to the back plate 58 and projects laterally to rotatably support a movable sheave 64.

The hydraulic hoses 45, 46 are led forwardly from the hose clamp 53 to the movable sheave 64 and wound around the latter in a bight to extend rearwardly therefrom to the fixed sheave 50. The hydraulic hoses 45, 46 are led around the sheave 50 and then forwardly therefrom to extend into the second boom section 27 and the third boom section 28 to the cylinder 40, and are connected to opposite ends of the latter by suitable hydraulic fittings.

When the second boom section 27 is in its retracted position relatively to the first boom section 26, the cylinder -40 is in its innermost position, as seen in FIG. l. In this position of the cylinder 40, the trolley 57 and the movable sheave 64 are in their forwardmost position on the rail 55, also as seen in FIG. l. In this position of the movable sheave 64, the hydraulic hoses 45, 46 are withdrawn from the second boom section 27 and the third boom section 28, and extend around the fixed sheave 50` and the movable sheave 64.

The back plate 58 of the trolley 57 has a lateral leg 65 to which there ,is secured one end of a long coil spring 66 by screw and nut means 67. The other end of the coil spring 66 is secured to the first boom section 26 by screw and nut means 68 on a bracket 69. The coil spring 66 urges the trolley 57 to its forwardmost position on the rail S5. When the hydraulic hoses 45, 46 are drawn into the second boom section 27 and the third boom section 28, they are pulled out ove'r the fixed sheave 50 and the movable sheave 64, in opposition to the force of the coil spring 66 as the trolley 57 travels to the rear. The hoses `45, 46 are withdrawn from the second boom section 27 and the third boom section 28 by the force of the' coil spring 66 acting on the trolley 57 to cause it and the movable sheave 64 to travel forwardly along the rail 55. There is a cover 70 for the fixed sheave 50, the rail 55, the trolley 57, and the coil spring 66 that extends along the first boom section 26 and is secured to the latter on its side wall 31 by a plurality of screws 71.

There is a storage length of the hydraulic hoses 45, 46 which is disposed along the crane boom 10 in a bight around the movable sheave 64. Such stored length of the hoses `45, 46 is about twice as long as the rail 55 on which the trolley 57 rides. The hydraulic hoses 45, 46 are readily pulled out from the storage length thereof or returned, according to the travel of the hydraulic cylinder 40 with the second and third boom sections 27, 28 thereby to maintain the connections of the hydraulic hoses 45, 46 to the cylinder 40 in all positions of travel of the latter.

Obviously those skilled in the art may make various change's in the details and arrangement of parts.

Having thus described and shown an embodiment of the invention, what it is desired to secure by Letters Patent of the United States is:

1. An extensible and retractable boom construction comprising, a first hollow walled boom section, a second hollow lwalled boom se'ction, a third hollow walled boom section, each of said first, second and third boom sections being elongated members, said second boom section being telescopically received within said first boom section and said third boom section being telescopically receivedl within said second boom section, means to extend and to retract said second boom section and said third boom section relatively to said first boom section, double acting hydraulic cylinder means disposed within and connected to said second boom section and to said third boom section to extend and to retract said third boom section relatively to said second boom section, first and second hydraulic lines connected to said hydraulic cylinder means for supply flow and for return flow of hydraulic fluid to the hydraulic cylinder, a first guide element mounted on the inner end of said first hoorn section on a wall of the first boom section, said first guide element overlapping said wall of the first boom section, said hydraulic lines being led from outside said Wall of the first boom section over said first guide element to change the direction of the hydraulic lines to extend into the first boom section at the inner end thereof for connection of said hydraulic lines to said hydraulic cylinder means, a movable guide element for said hydraulic lines in which the hydraulic lines are led around the movable guide element to change the direction of the hydraulic lines to lead the hydraulic lines to said first guide element, and means on said first boom section to support said movable guide element for movement along said rst boom section to pay out said hydraulic lines in one direction of movement of the movable guide element towards said first guide element and to take up said hydraulic lines in the opposite direction of movement of said movable guide element away from the first guide element.

2. An extensible and retractable boom construction as recited in claim 1 in which said first guide element comprises a sheave mounted on an upright pivot pin on said wall of said first boom section to lead the hydraulic lines into the first boom section, said support means comprises a track secured to said Wall of said first boom section in proximity to the wall and extending along the first boom section in the longitudinal direction to said first guide element sheave, and said movable guide element comprises a sheave and movable means engaged with said track to move the movable guide element sheave back and forth along said track.

3. An extensible and retractable boom construction as recited in clairn 2 including elongated spring return means for said movable sheave, said elongated spring return means being attached to said movable means and to said first boom section and disposed in longitudinal alignment with said track to take up said hydraulic lines when said second and third boom sections are retracted relatively to said first boom section.

4. An extensible and retractable boom construction comprising, a first boom section, a second boom section, a third boom section, said second boom section being telescopically received within s aid first boom section and said third boom section being telescopically received within said second boom section, means to extend and to retract said second boom section and said third boom section relatively to said first boom section, a hydraulic cylinder disposed Within and connected to said second boom section and to said third boom section to extend and to retract said third boom section relatively to said second boom section, a hydraulic line connected to said hydraulic cylinder for hydraulic fiuid for the hydraulic cylinder,

a first guide element fixedly mounted on the inner end of said first boom section, a rail secured to said first boom section and extending along the' first boom section in the longitudinal direction from said first guide element, a second guide element mounted on said rail to be movable along the rail back and forth in the longitudinal direction of said first boom section, said hydraulic line being le'd around said second guide element and along said first boom section and then around said first guide element and into the inner end of said first boom section and connected to said hydraulic cylinder, resilient means to urge said second guide element to one end of said rail that is remote from the inner end of said first boom section and the second guide element moving toward the inner end of said first boom section as the second and the third boom sections are extended relatively to the first boom section and the hydraulic line is pulled around the second guide element and around the rst guide element and into and through the first boom section.

5. An extensible and retractable boom construction as recited in claim 4 in which said first guide element comprises a rotatable sheave, said second guide element cornprises a rotatable sheave, a trolley for said second guide element, wheels for said trolley to engage said rail and to ride back and forth on the rail with the second guide element, and said resilient means comprising a spring secured to the trolley and to said first boom section.

6. An extensible and retractable boom construction as recited in claim 5 in which said hydraulic cylinder is a double acting cylinder and there are' two hydraulic lines connected to the double acting cylinder within said second and third boom sections, and two hydraulic lines being led through said first boom section around said first sheave guide element and then along the first boom section and around said second sheave guide element to draw the two hydraulic lines into the first boom section as the second and third boom sections are extended and to withdraw the two hydraulic lines from the first boom section as the second and third boom sections are retracted.

7. An extensible and retractable boom construction as recited in claim 5 in which said rail is secured to a side wall of said first boom section in proximity to the side wall, said first sheave guide element is secured to said side wall of said first boom section on an upright pivot pin to be rotatable on the pivot pin about an upright axis, said se'cond sheave guide element is mounted on a lateral shaft to be rotatable on the shaft about a lateral axis, said hydraulic line being led around said second sheave guide element to said first sheave guide element and around the first sheave guide element to change the direction of the hydraulic line and to lead the hydraulic line around the inner end of said side wall of the first boom section and into the first boom section to said hydraulic cylinder.

8. An extensible and retractable boom construction as recited in claim 5 in which said rail is secured to a side wall of said first boom section in proximity to the side wall, said trolley wheels are disposed above and below said rail in engagement with the rail to hold the trolley on the rail as it rides back and forth, said spring is disposed in alignment with said rail and extends along said side Wall of the first boom section in a longitudinally forward direction from the rail, the forwardmost end of said spring being secured to said side wall of the first boom section.

References Cited UNITED STATES PATENTS 3,042,234 7/1962 Davis 212--55 3,289,869 12/1966` Hoyt 187-9 3,300,060 1/1967 Lado 212-144 HARVEY C. HORNSBY, Primary Examiner U.S. Cl. X.R. 

